The invention relates to a portable surface processing apparatus with two oppositely motor-driven rotor cages with horizontal axes, a plurality of processing elements arranged on cage bars of the cages, and adjustable wheels arranged to raise and lower the rotor cages.
Such apparatuses are known, for example, from U.S. Pat. No. Des. 252,880 and are constructed both as hand tools, as well as larger apparatus movable on rollers. In such apparatus the rotor can be driven both by an electric motor, and by a combustion motor. An alternative drive can also be a pneumatic motor.
The apparatus serves for surface processing, such as rust removal from relatively large surfaces, removing old paint, cleaning dirty concrete floors, etc. The processing remains restricted to the surface; the processing depth is, to be sure, adjustable, but only slightly. The processing is accomplished by the processing elements arrayed on the rotor cage bars, such as, for example, blades.
The above-mentioned known apparatuses have only one rotor cage. This has the disadvantage that the processing force acts in one direction upon the surface being treated, so that the apparatus has the tendency to move automatically in one direction. In the opposite direction, however, it can be shifted only with difficulty. This undesired reaction force is especially pronounced in the case of relatively heavy and larger apparatus.
From German Pat. No. 509,435 and U.S. Pat. No. 2,588,707 there are known, further, surface processing machines with two oppositely motor-driven rotors which are suited for shaving, grinding or polishing of wood floors. The rotors of these patents rest directly on the surface to be processed.